Beat egg yolks in a large bowl; mix in 1/3 cup sugar and salt.
Combine heavy cream, pumpkin pie spice, and vanilla extract in a pot over low heat. Cook, stirring occasionally, until the temperature of the liquid reaches 158 degrees F (70 degrees C), 2 to 4 minutes; do not overheat.
Pour hot cream mixture slowly into the beaten egg yolks. Pour cream-egg mixture slowly through a sieve into a separate bowl. Let settle until froth is reduced, about 20 minutes.
Transfer the cream-egg mixture into 4 Mason jars. Flash the tops of the cream with a kitchen torch to remove any bubbles. Place lids on jars and finger tighten. Immerse jars in a water bath with a sous vide cooker set to 176 degrees F (80 degrees C); cook for 1 hour.
Remove jars and let cool until safe to handle, at least 15 minutes. Prepare a large bowl with ice and water.
Place jars in the ice bath until completely cool, at least 20 minutes. Remove lids and sprinkle 1 tablespoon sugar over the surface of each creme brulee. Torch the tops slowly using low gas at a moderate distance from the jars until sugar caramelizes, a few seconds each. Let stand until surfaces harden, about 5 minutes.